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Okay, here I go,

This is my first technical inquiry into this forum. I have read a number of comments that set-up is the most common problem area for achieving the best sound from a resonator. I read and saw on the Schoonover website, his solution to achieving the best contact between the bridge and spider. I understand and agree that the mechanical transfer of energy is hindered by an improper fit at this point. Schoonover's solution to redesign is quite interesting and with a new build in the future I may try one of his spider/bridge units.

However, when working with a cast spider, is the bridge base molding really so imprecise that complete contact is that hard to achieve? I have some ideas about utilizing my piano rebuilding techniques for fitting pin blocks to plates to this problem, but don't want to pursue an idea that really has no basis or has a simpler solution.

Okay, all you guru's enlighten this wondering pilgrim..

Ken,

While I've only done a couple of complete setups, I attended a Tim Scheerhorn workshop where he went through a complete setup and in a nutshell he said that a resonator setup is a series of layers that all have to be correct (i.e. cone to guitar body, spider to cone, bridge to spider, string to bridge). Here's what I've found through my research and what I've done for the bridge to spider fitting:

The bridge slot in the spider should be flat and the inside corners cleaned up. Ultimately, you want the bridge insert bottoms to securely contact the bottom of the spider slot. Any unevenness of the spider slot will prevent the bridge from seating against the spider. Ideally, I'd like to be able to mill the slot to get it nice and clean but I don't have a mill so I use a file and sanding sticks to clean it up to the best of my abilities. I believe who you buy your spiders from also dictates how well this prep work will have been done. The Beard spiders I have used have been pretty good. I don't have experience with any other spider suppliers but would love to hear from folks who have.

Measure the slot width and sand the bridge blank to slightly over sized (approx. .005") You want a friction fit that will snugly hold the bridge but that will not damage it when pressing in the insert.

Break the edges of the corners on the bottom of the inserts. This will allow the bottom of the inserts to contact the bottom of the slot.

Use a vice to press in the inserts (you can also use a clamp with cauls). This I got from StewMacs Trade Secrets Book #2 featuring Tim Scheerhorn. I did both inserts at the same time thinking that it would make the tops of both inserts the same height and make string slotting easier but in the future I will try doing one at a time to ensure that I have bottomed out both inserts then sand and crown the inserts to the same height after they are installed.

With all that said, I really like the Schoonover setup and I think I would probably try his bridge/spider using the Fishman pickup (I believe Mike Witcher uses this setup in his rig and likes it). His approach of doing away with the press fit and directly attaching the bridge seems to address a lot of the problems inherent in the design (and makes installing the Fishman pickup without damaging it a no-brainer). Beard also has a solution which has a clamping mechanism on the spider and a couple of screws that hold the bridge insert (this is the setup in the Beard Jerry Douglas model with the Fishman pickup). Worth checking out. If you have another idea for fitting the bridge to the spider let's hear it!

Ron

Ron, I am not sure if it will improve the setup but it will create a solid connection between the bridge and spider. I can't seem to find any mention of someone else trying it, so it is either new or just over kill.

When fitting a piano pinblock to the plate you must have solid contact between the two or tuning stability is effected by the possible movement created by the almost 20 ton stress of the strings at concert pitch. With the contrasting materials of cast iron and wood, it is extremely labor intensive to make a void free surface on both. To solve this, rebuilders use marine epoxy to fill the gaps. Place wax paper in the spider bridge slot and then insert a small amount of the epoxy, enough to fill any gaps in a rough surface, and then press in the bridge insert. Once dry you will have complete void free contact between the two.

However, in piano work the epoxy has only to fill the gaps and does not transfer string energy. With a resonator it will be part of the energy transfer process and I do not know how it will effect that. I realize that purchasing a higher grade spider or using the Schoonover modular unit may make this unnecessary, but if you have a spider that has casting issues this might be a solution. I do not know how long it would take to mill a better slot if the equipment was available, but I do know this process is relatively straight forward and requires minimal equipment needs. It could even eliminate the need for concerns over a bridge insert that was slopping fitting.

I was just pondering the possibilities of a process transfer from one building technique to another. It may really only be academic and not practical but thanks for asking. I try not to be a geek but my academic side comes out sometimes.

Besides, someone may have tried it already and the ignorance of my inexperience may be showing